SARITA - The 260-foot-tall wind turbines of the Kenedy Ranch stand like a steel forest along the edge of the Laguna Madre and pump out hundreds of megawatts of emission-free electricity.
The spinning blades, alongside some of the most important habitat in Texas and one of North America's largest migratory flyways, are killing thousands of birds and bats each year.
How many isn't publicly known because, unlike California counties, Texas and the federal government don't require turbine operators to make public reports, according to state and federal officials.
Aside from the quantity of bird and bat deaths, a more complicated question remains unanswered as more wind turbines are put up along the Texas Coast: Have the turbines changed the ecosystem and displaced wildlife?
For the first time, Pattern Energy, which owns 118 turbines on the ranch, and Iberdrola Renewables, which owns 168, voluntarily released results of their first yearlong studies.
Pattern estimates up to 921 birds and 2,309 bats were killed between Aug. 24, 2009, and July 31; Iberdrola's estimates: 1,812 birds and 3,087 bats for the same period.
While the bird killings match the national average, one researcher found the bat killings much higher than expected.
Those who opposed the wind farms are not convinced the studies are credible or conclusive.
The work was paid for by the companies and not peer-reviewed. In their reports, biologists wrote about the challenges of collecting good data with rattlesnakes biting their search dogs and cows that would not leave. The researchers estimate scavengers removed half of the bird and bat carcasses before they could be found.
They also could not get federal permits to collect the species they did find, so many had to be marked as unknown.
After more than a year of submitting forms, the companies received a collection permit last month, said Rick Greiner of Pattern Energy.
But of the species identified, none were endangered.
"We think there is a low impact to T and E (threatened and endangered species) because we have not found any," he said.
The reports state the wind farms had a bird mortality rate of three birds per megawatt, which is in the middle for the national average of one to six birds, according to the American Wind Energy Association, a trade group. A national average for bats killed per megawatt is not well-established.
In addition to average bird mortality, the companies point to the high-tech radar systems they voluntarily installed that will trigger a shutdown of the spinning turbines during fog or low visibility when a mass of birds or bats is approaching.
As of the end of 2010, a shutdown had not occurred.
"At every stage of the project's life, Iberdrola Renewables has gone above and beyond what has been required by the state of Texas and federal government to conduct extensive studies and monitor the outcomes of our wildlife protection measures," said Jan Johnson, a spokeswoman for Iberdrola.
More than numbers
One who disagrees the studies have been extensive is David Newstead, an environmental scientist for the Coastal Bend Bays & Estuaries Program in Corpus Christi and president of the Coastal Bend Audubon Society.
He believes mortality rates are an incomplete measurement of the effect of wind farms. The numbers do not reflect how turbines could be changing behavior of birds and bats by forcing them out of their habitat and putting them under greater stress.
"Cumulative effects are practically never discussed by wind developers," Newstead said. "At the end of the day, the most important numbers, for the sake of the wildlife, is how many of what species of birds and bats are being not only killed, but displaced."
Newstead is one of most vocal challengers to the construction of wind farms along the Texas Coast and was part of an unsuccessful lawsuit to stop them, funded in large part by the King Ranch, which borders the Kenedy Ranch.
"There is no other place in North America that plays such an important role for so many species during some part of their lives," Newstead said about the Laguna Madre and surrounding grasslands. "Collision mortality can thus affect any of more than 400 regularly occurring species."
Newstead's concerns for the coast only grow as more turbines are built, following the lead of the Kenedy Ranch.
Since the Kenedy turbines came online in 2009, Iberdrola has added more, and the Papalote Creek Wind Farm with 196 units was built outside Corpus Christi, according to AWEA.
When operating at capacity, the Kenedy Ranch turbines in total can generate close to 680 megawatts, or enough electricity to meet the needs of 135,000 to 170,000 homes, according to CPS Energy, which buys power from Iberdrola.
That power is produced during the day when consumer demand is the highest, and it can be delivered via uncongested transmissions lines, said CPS Energy spokeswoman Lisa Lewis, adding that effect on wildlife was not considered when it signed the contract.
Working with wind
For now, wind companies face few consequences for killing wildlife, explained Paul Schmidt, assistant director at the Migratory Bird Program for the U.S. Fish and Wildlife Service.
While it's against federal law to kill or harm any endangered, threatened or migratory bird species, the agency has not prosecuted any wind farm owner.
Instead, the service is working with the wind industry, scientists and conservationists to establish guidelines for how wind companies should place and operate a wind farm, Schmidt said.
A draft of those guidelines was released for comment this month.
Once the guidelines are adopted, the Fish and Wildlife Service will have a basis to decide which companies to investigate, Schmidt said.
"It's just like you're driving down the highway and the speed limit is 55," he said. "You can go 60, probably 62, but at some point you are going to get caught."
Schmidt said companies that volunteer information will avoid the scrutiny given those that do not.
Pattern and Iberdrola have regular communication with the service. But the reports they send are marked "privileged and confidential," so they can't be shared.
When Pattern gave its reports to the San Antonio Express-News, it called them public but then requested it preapprove anyone who saw them and that they not be posted online.
"Clearly we have a problem with transparency with the wind and wildlife issues, and I think we have a ways to go," said Edward Arnett, director of programs at Bat Conservation International, whom Pattern approved to review its studies.
With wind farms across the country reluctant to share data openly, the understanding of the cumulative effect on wildlife and the best way to minimize it are stunted, Arnett said. This is especially true of bats.
At 150 feet long, the wind turbine blades move between 100 and 180 mph at their tip. The pressure change on the trailing edge is enough to cause internal hemorrhaging in bats, according to Bat Conservation International.
Before the Kenedy wind turbines went in, Arnett had expected low bat mortality, as there were no known concentrations of bats in the area. Since so little is known about bat movements, he is not surprised the numbers turned out to be higher.
Before wind turbines were built, little was known about bat movements.
It isn't possible to know what is and isn't working, he said.
"Until we have the information published in a credible fashion that is publicly shared and published in journals, it is going to be unknown," he said.